U.S. patent number 7,245,441 [Application Number 11/238,752] was granted by the patent office on 2007-07-17 for document camera having zoom-indication function.
This patent grant is currently assigned to Avermedia Technologies, Inc.. Invention is credited to Jung-Yu Chen, Po-Chih Hung, Jiun-Shin Wu, Yung-Hsi Wu.
United States Patent |
7,245,441 |
Wu , et al. |
July 17, 2007 |
Document camera having zoom-indication function
Abstract
A document camera is used to show image of an object on a
display. In the document camera, a first image data of the object
obtained by a video-capturing device is derived into a second image
data and a third image data by an image processor in response to a
zoom operation, wherein the second image data results in a zoomed
image of the object and the third image data results in a scaled
image of the object. In response to the zoom operation, there is
also a mark frame data generated by a position information
controller, which results in a mark frame. The zoomed image, scaled
image and mark frame are then synthesized into a combined image by
an image synthesizer, and the mark frame superimposes the scaled
image to indicate a result of the zoom operation.
Inventors: |
Wu; Jiun-Shin (Taipei,
TW), Chen; Jung-Yu (Taipei, TW), Wu;
Yung-Hsi (Taipei, TW), Hung; Po-Chih (Taipei,
TW) |
Assignee: |
Avermedia Technologies, Inc.
(TW)
|
Family
ID: |
37493861 |
Appl.
No.: |
11/238,752 |
Filed: |
September 29, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20060274428 A1 |
Dec 7, 2006 |
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Foreign Application Priority Data
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Jun 2, 2005 [TW] |
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94118250 |
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Current U.S.
Class: |
359/676;
348/207.1; 348/207.11; 396/430 |
Current CPC
Class: |
G03B
17/04 (20130101); H04N 1/00129 (20130101); H04N
1/3875 (20130101); G03B 17/561 (20130101); G03B
17/54 (20130101); H04N 2201/0434 (20130101) |
Current International
Class: |
G02B
15/14 (20060101); G03B 19/00 (20060101); H04N
5/225 (20060101) |
Field of
Search: |
;359/676
;348/207.1,207.11 ;396/430 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mack; Ricky
Assistant Examiner: Choi; William
Claims
What is claimed is:
1. A document camera for showing image of an object on an image
display, comprising: a video-capturing device for picking up an
initial image of the object to realize a first image data; an image
processor electrically connected to said video-capturing device for
deriving a second image data and a third image data from said first
image data in response to a zoom operation, wherein said second
image data results in a zoomed image of the object and said third
image data results in a scaled image of the object; a position
information controller electrically connected to said image
processor for generating a mark frame data in response to said zoom
operation, wherein said mark frame data results in a mark frame;
and an image synthesizer electrically connected to said position
information controller and said image processor for synthesizing
said zoomed image, said scaled image and said mark frame to
generate a combined image shown on the image display, wherein said
mark frame superimposes said scaled image to indicate a result of
said zoom operation.
2. The document camera according to claim 1 wherein said
video-capturing device is a module comprising: an image sensor for
receiving and converting a light intensity reflected from the
object into an analog signal; and an analog-to-digital converter
for converting said analog signal into said first image data.
3. The document camera according to claim 1 wherein said first
image data, said second image data, said third image data and said
mark frame data include coordinates of respective start points on
the image display.
4. The document camera according to claim 1 wherein said scaled
image overlays a corner of said zoomed image, and said mark frame
variably superimposes said scaled image according to the
relationship between said zoomed image and said initial image.
5. The document camera according to claim 1 wherein said zoom
operation is a zoom-in operation, said second image data is
obtained according to a specified zoom-in ratio n, said third image
data is obtained according to a specified contraction ratio m, and
said mark frame data is obtained according to said specified
zoom-in ratio n and said specified contraction ratio m.
6. The document camera according to claim 5 wherein said mark frame
data includes position information and size information.
7. The document camera according to claim 6 wherein said position
information and said size information correlate to the product
m.times.n.
8. The document camera according to claim 1 further comprising a
digital-to-analog converter electrically connected to said image
synthesizer for converting said combined image data into an analog
image data for display.
9. The document camera according to claim 1 wherein said image
processor, said position information controller and said image
synthesizer are integrated into a single chip.
Description
FIELD OF THE INVENTION
The present invention relates to a document camera, and more
particularly to a document camera used with an image display to
show an object with zoom indication.
BACKGROUND OF THE INVENTION
Multimedia processing technology is very widely applied to
electronic products in the market, such as PDAs (Personal Digital
Assistants), cellular phones, digital cameras, high-definition
digital TVs and document cameras. For implementing the multimedia
processing technology, DSP (Digital Signal Processor) is commonly
used in these electronic products.
The DSP is advantageous of processing a large number of input
digital signals at one time, and quickly executing operations to
reach the Real-Time performance. The special DSP hardware and
command designs facilitate the accomplishment of complicated
control and various additional functions required by respective
electronic products. Unlike the traditional microprocessor, the DSP
has improved command execution speed, performance and Real-Time
performance, so the DSP plays an important role on multimedia
processing technology.
Taking a document camera as an example, it is popularly used in a
regular meeting or an academic conference to show some literal or
graphical data in order to facilitate the presentation or
discussion of a document, chart or academic thesis. Compared with
the traditional transparency projectors, the document cameras not
only exhibit better image quality and versatile functions but also
easier in preparing material to be shown. For example, the
documents or charts do not have to be printed on the transparent
projection slices as they used to do with the traditional
transparency projector. Furthermore, a document camera is generally
more compact is size than a traditional transparency projector and
thus is inconvenient for carrying and storing.
A document camera is typically incorporated therein the
architecture of a scanner or a video camera for performing digital
image scanning, image capturing, and image outputting functions.
So, a document camera may be equipped with a video-capturing module
generally used in a digital still camera, digital video camera or
cellular phone to execute the image pickup function. An image
sensor, which is implemented with a complementary
metal-oxide-semiconductor sensor (CMOS sensor) or a Charge Couple
Device (CCD), is used in the video-capturing module to pick up the
image of an object positioned in front of the video-capturing
module, and an image display is used with the document camera for
showing the image of the object captured by the image sensor. For
example, the image display can be a monitor of a TV set, a display
of a computer system or a projection screen showing images via the
protection of a digital projector. In this way, the document or
chart can be displayed in a live video manner. Also, the
utilization of a document camera vivifies the presentation due to
its functional varieties. Therefore, a document camera is expected
to replace the traditional transparency projector in near
future.
Please refer to the example shown in FIG. 1(a). A document camera
10 is coupled to a digital projector 20 and a projection screen 21
is arranged a proper distance from the digital projector 20. The
image of the object 1 captured by a video-capturing module 11 is
processed by the document camera 10 and then outputted to the
digital projector 20 to be shown on the projection screen 21. By
placing the object in of the focusable range of the video-capturing
module 11, the document camera 10 will be able to process the image
of object 1 and show it as a live video on the projection screen 21
via the digital projector 20. In addition to showing images via the
digital projector 20 and the projection screen 21, the images
captured by the document camera 10 can also be shown on an image
display directly coupled to the document camera 10, such as a
monitor of a TV set or a display of a computer system. For most
document cameras, there is a focus adjusting device (not shown)
arranged in the video-capturing module 11 for manually zooming in
or zooming out the object 1 to focus on a specific area that the
user is interested in.
Please refer to FIG. 1 (b). It shows a functional block diagram of
the document camera 10. Conventionally, the document camera 10
includes a video-capturing module 101, a digital signal processor
(DSP) 102 and a digital-to-analog converter (DAC) 103. The
video-capturing module 101 includes an image-sensor 1011 and an
analog-to-digital converter (ADC) 1012. In the image sensor 1011,
the received light intensity from an object is converted into
corresponding amount of charges through photoelectrical conversion
and then outputted as an analog signal. The analog signal is then
converted into a digital image data by the ADC 1012 and transmitted
to the DSP 102 for further processing, e.g. zoom-in or zoom-out
operations of the digital image data. Afterwards, the DAC 103
converts the processed digital image data into an analog image data
and outputs it to an image display 104 for display.
Although zoom-in and zoom-out operations have been feasible in
conventional document cameras, only a specific area of the object
is shown the image display after the zoom-in or zoom-out operation.
However, it is usually hard to figure out the position of the shown
specific area relative to the full size image after a zoom-in
operation. Particularly, the higher the zoom-in ratio is, the less
recognizable the image becomes. Under this circumstance, the user
generally needs to zoom in and out the image several times to
locate the specific area in order to well perform a pan operation
subsequently. It is apparently a time-wasting and inconvenient task
for the user.
SUMMARY OF THE INVENTION
Therefore, one object of the present invention is to design a
document camera having a zoom-indication function so that the user
can locate the zoom-in area of the object readily.
The present invention provides a document camera for showing image
of an object on an image display. In the document camera, a
video-capturing device is used for picking up an initial image of
the object to realize a first image data. An image processor is
electrically connected to the video-capturing device for deriving a
second image data and a third image data from the first image data
in response to a zoom operation, wherein the second image data
results in a zoomed image of the object and the third image data
results in a scaled image of the object. A position information
controller is electrically connected to the image processor for
generating a mark frame data in response to the zoom operation,
wherein the mark frame data results in a mark frame. An image
synthesizer is electrically connected to the position information
controller and the image processor for synthesizing the zoomed
image, the scaled image and the mark frame to generate a combined
image shown on the image display, wherein the mark frame
superimposes the scaled image to indicate a result of the zoom
operation.
In an embodiment, the video-capturing device is a module
incorporating therein an image sensor for receiving and converting
a light intensity reflected from the object into an analog signal,
and an analog-to-digital converter for converting the analog signal
into the first image data.
The first image data, the second image data, the third image data
and the mark frame data preferably include coordinates of
respective start points on the image display.
Optionally, the scaled image overlays a corner of the zoomed image,
and the mark frame preferably variably superimposes the scaled
image according to the relationship between the zoomed image and
the initial image.
For example, the zoom operation is a zoom-in operation, the second
image data is obtained according to a specified zoom-in ratio n,
the third image data is obtained according to a specified
contraction ratio m, and the mark frame data is obtained according
to the specified zoom-in ratio n and the specified contraction
ratio m. Specifically, the mark frame data includes position
information and size information correlating to the product
m.times.n.
In an embodiment, the document camera further comprises a
digital-to-analog converter electrically connected to the image
synthesizer for converting the combined image data into an analog
image data for display.
The image processor, the position information controller and the
image synthesizer can be integrated into a single chip.
BRIEF DESCRIPTION OF THE DRAWINGS
The above contents of the present invention will become more
readily apparent to those ordinarily skilled in the art after
reviewing the following detailed description and accompanying
drawings, in which:
FIG. 1(a) is a schematic diagram illustrating a typical document
camera for use with a digital projector and an image display;
FIG. 1(b) is a functional block diagram illustrating a conventional
document camera;
FIG. 2 is a functional block diagram of a document camera according
to a first embodiment of the present invention;
FIG. 3 is a scheme exemplifying the image change accomplished by
the document camera of FIG. 2 after a zoom-in operation; and
FIG. 4 is a functional block diagram of a document camera according
to a second embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
For imparting a zoom-indication function to a document camera, a
position information controller and an image synthesizer are
arranged in the document camera to locate the zoomed area according
to the present invention. Please refer to FIG. 2 which illustrates
a first embodiment of the document camera with zoom indication. The
document camera 200 is used to show an object 2 on an image display
22. For example, the object 2 may be a paper document of general
size, and the image display 22 may be a monitor of a TV set, a
display of a computer system or a projection screen with the aid of
a digital projector (refer to FIG. 1(a)).
In this embodiment, the document camera 200 includes a
video-capturing module 201, an image processor 202, a position
information controller 203 and an image synthesizer 204. The
video-capturing module 201 includes an image sensor 2011 and an
analog-to-digital converter (ADC) 2012. For example, the image
sensor 2011 is constructed by a Charge Couple Device (CCD) or a
complementary metal-oxide-semiconductor sensor (CMOS sensor). The
image sensor 2011 converts the light intensity reflected and
received from the object 2 into an analog signal and then outputs
the analog signal to the ADC 2012 to be converted into a digital
image data to be shown on the image display 22.
The image processor 202 of the document camera 200 is electrically
connected to the video-capturing module 201 for processing the
digital image data when necessary. For example, when the user
manipulates the operational interface, e.g. a control panel or
remote controller (not shown) of the document camera 200, to do a
zoom-in operation, the zoom-in information including the zoom-in
ratio and the starting point of the zoomed area as well as the
digital image data will be referred to by the image processor 202
in order to show a specific area of the object 2 in an enlarged
manner. According to the present invention, in addition to the
enlarged image of the specific area of the object 2, a contracted
image of the object 2 for zoom indication is also created by the
image processor 202 to be shown on the image display 22 along with
the enlarged image of the specific area of the object 2. This
purpose is achieved by the image synthesizer 204.
The image synthesizer 204 is electrically connected to the image
processor 202 for combining the image data of the enlarged image 31
and the contracted image 32, as illustrated in the scheme of FIG.
3. Moreover, for indicating which part of the full size image 30 of
the object 2 has been zoomed in and shown as the main frame 31, a
mark frame 34 is further created by the position information
controller 203. Being processed by the image synthesizer 204, the
synthesized image 33 consists of a main frame 302 equivalent to the
image 31, an overlay image 303 equivalent to the image 32 and
another overlay image equivalent 3031 to the mark frame 34. The
mark frame image 3031 is marked on the contracted overlay image 303
to show the zoomed part of the image 30 so that the user can well
realize the result of the zoom operation and thus can do any
subsequent pan operation properly. As the synthesized image data
resulting from the image synthesizer 204 is in a digital format, a
digital-to-analog converter (DAC) 205 is provided in the document
camera 200 to convert the resulting image data into an analog image
data suitable to be shown on the image display 22. The position
information controller 203 for creating the mark frame 34 is
electrically connected to the image processor 202 and the image
synthesizer 204. The mark frame 34 is created according to the
information of the zoom-in ratio, the starting point of the zoomed
area 301 and the contraction ratio of the overlay image 32. An
example for illustrating the synthesis of these images 31, 32 and
34 will be described hereinafter.
In this example, the coordinates of the start point P(a,b) of the
full size image 30 obtained by the video-capturing module 201 is
set to be P(1,1) and the image 30 includes 800.times.600 pixels.
Then, it is assumed that the coordinates of the starting point
Q(p,q) of the zoomed area 301 are Q(401, 1), the zoom-in ratio n
from the image portion 301 to the image 31 is 4, and the
contraction ratio m from the image 30 to the image 32 is 8.
Accordingly, the zoom indication overlay image 303 occupies 1/8 of
the displayed image 33 and the mark frame 3031 occupies 1/32 of the
image 33. The coordinates of the starting point S(u,v) of the zoom
indication overlay image 303 are S(800-800/(8).sup.1/2,1), and the
coordinates of the starting point of the starting point R(r,s) of
the mark frame 3031 are R(800-800/(32).sup.1/2,1). According to the
above information, not only the zoomed image can be shown but also
which part of the full size image 30 of the object 2 is zoomed in
can be illustrated. The scaling ratio of the zoom indication
overlay image 303 may be preset. Under this circumstance, the
coordinates of the starting point S(u,v) of the zoom indication
overlay image 303 will be fixed at S(800-800/(8).sup.1/2,1) without
change with the zooming ratio, and only the position and the size
of the mark frame 3031 vary with the zoom ratio. Furthermore, when
the user digitally pans, zooms in or zooms out the image to another
specific area via the operation interface, the position of the mark
frame 3031 relative to the contracted image 303 can be used to
clearly show the current displaying status of the object 2 for the
user's reference.
Please refer to FIG. 4, in which a functional block diagram of a
document camera 400 according to a second embodiment of the present
invention is shown. The document camera can also be used to show
the object 2 on the image display 22. In this embodiment, the image
processor 4021, position information controller 4023 and image
synthesizer 4022 of the document camera 400, which perform in a
manner similar to those illustrated in the embodiment of FIG. 2,
may be integrated into a single chip and functions as a digital
signal processor (DSP) 402. The DSP 402 is disposed between the
video-capturing module 401 and DAC 403 for processing the image
obtained by the video-capturing module 401 into a desired format as
described above with reference to FIG. 3 and then having the
processed image shown on the image display 22 via the DAC 403.
To sum up, as the image synthesizer and the position information
controller are arranged in a document camera according to the
present invention, the document camera can exhibit a
zoom-indication function with a contracted overlay image in
addition to the display of the target image. Furthermore, a mark
frame superimposes a specific area of the contracted overlay image
for indicating which part of the target image is currently shown.
It is particularly advantageous when a zoom-in operation is
performed, and facilitates subsequent panning operations
While the invention has been described in terms of what is
presently considered to be the most practical and preferred
embodiments, it is to be understood that the invention needs not be
limited to the disclosed embodiment. On the contrary, it is
intended to cover various modifications and similar arrangements
included within the spirit and scope of the appended claims which
are to be accorded with the broadest interpretation so as to
encompass all such modifications and similar structures.
* * * * *